[PATCH] integrity/ima: Provide Kconfig option for ima-modsig template
michael.weiss at aisec.fraunhofer.de
Mon Feb 15 15:36:51 UTC 2021
On Mon, 2021-02-15 at 08:26 -0500, Mimi Zohar wrote:
> Hi Michael,
> On Mon, 2021-02-15 at 11:23 +0100, Michael Weiß wrote:
> > 'ima-modsig' was not in the list of selectable templates in Kconfig.
> > The missing Kconfig options were added to support the ima-modsig
> > template as default template.
> > Signed-off-by: Michael Weiß <michael.weiss at aisec.fraunhofer.de>
> Since 'ima-modsig' is only needed for appended signatures (e.g. kexec
> kernel image on powerpc, kernel modules) a per policy rule "template="
> option was defined. There's also the 'ima_template=' boot command line
> option. Between these two options, I didn't see the need for making
> it a build time default option. Do you?
The use-case I had in mind was a simple measured boot,
no user-space applications, only to measure already signed modules
which are already signed by modsig
using a single policy line:
I thought for this purpose, we could just compile in the default
template to be modsig but it wasn't
I have overlooked the policy rule "template=",
In the above use-case, it also just works to set the policy:
measure func=MODULE_CHECK template=ima-modsig
So, your are right maybe that is not necessary.
> The patch itself looks good.
> > ---
> > security/integrity/ima/Kconfig | 3 +++
> > 1 file changed, 3 insertions(+)
> > diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
> > index 12e9250c1bec..32b9325f49bf 100644
> > --- a/security/integrity/ima/Kconfig
> > +++ b/security/integrity/ima/Kconfig
> > @@ -78,6 +78,8 @@ choice
> > bool "ima-ng (default)"
> > config IMA_SIG_TEMPLATE
> > bool "ima-sig"
> > + config IMA_MODSIG_TEMPLATE
> > + bool "ima-modsig"
> > endchoice
> > config IMA_DEFAULT_TEMPLATE
> > @@ -86,6 +88,7 @@ config IMA_DEFAULT_TEMPLATE
> > default "ima" if IMA_TEMPLATE
> > default "ima-ng" if IMA_NG_TEMPLATE
> > default "ima-sig" if IMA_SIG_TEMPLATE
> > + default "ima-modsig" if IMA_MODSIG_TEMPLATE
> > choice
> > prompt "Default integrity hash algorithm"
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